Artificial stone and method of producing the same



June 9, 1931. 1,809,329

ARTIFICIAL STONE AND METHOD OF PRODUCING THE SAME J. B. BOSSI ET AL- MIMI! //v l E'N TORS 1' Mo? MM ATTORNEY Patented June 9, 1931 1 UNITED STA TES IPiATENT F E*1 JOHN B. BOSSI, OF ALLSTON, AND PAUL A. MAZZUCI-IELLI, OF NEWTON, MASSAGHU- I SETTS, ASSIGNORS'TO GAMBRIDG-E CEMENT STONE COMPANY, OF BRIGHTON,-MASSA CHUSETTS, A CORPORATION- OF MASSACHUSETTS ARTIFICIAL STONE AND METHOD OF PRODUCING THEv SAME Application filed September 11,1929. st am 391,728.! 1

This invention relates to artificial cast stone, and more particularly to improvements pertaining to the casting ofthe stone in a mold. 1 c i Artificial cast stone is extensively used in the construction of buildings and for various other purposes, and cast stone of any desired size and shape may be produced by pouring a stone producing compound containing hydraulic cement into a mold of the required size and shape.

The molds employed in casting artificial stone may be formed of metal vor other durable material in which case the same mold may be used over and over again, or the mold may be formed of damp or slightly moist molding sand in which case a new mold is made for each piece of. work cast. When a sand mold is employed a pattern formed of-wood, plaster of Paris or other material is firstflconstructed and the sand is placed about'thepattern to form the desired mold into which the stone-producing compound ispoured 7 surface of amold in accordance with the present invention is preferably pervious to @water so that the excess Water within the after the pattern has been removed.

While sand molds have been extensively used heretofore in casting artificial stone there is one undesirable result accompanying their use in that the cement of the stone producing compound grips'or adheres to the sand of the mold sothat when the cement mixture sets or becomes hard each face of the cast stone that has engaged a wallofthe mold is covered with sand. I This causes the texture and color of the c'aststone to'be concealed by the layer of sand that is firmly secured to the face of thestone by the cement. In order to overcome thisdiificulty ithas been the general practice heretofore to dress the face-or faces ofthe cast stone with a chisel, abrasive wheel or other cutting tool to, remove thesand of the mold from the surface of the stone, but the dressing of the surface of the cast stone with cutting tools is a time consuming and expensive operation. The present invention therefore relates to improvements in artificial caststone and in a method oftcasting' stone wherebythe sand of-the mold is prevented from adhering to or being gripped by the cement of the stone producing compound. f v

here to or be firmly the stone producing compound. p

I When the substance contemplated by the present invention is employed to treat a sand operation with water.

In carrying out the present invention the sand of the mold is prevented fromcontacting with and adhering to thesurfaces of the [cast stone by applying to one or more surfaces of the sand mold a fine powdery substance which will prevent the cement mixture from contacting directly with the sand of the mold, and which will not permanently adgripped by the cement of mold the'faces of the. caststo-ne adjacent-the .treated faces of the mold will be free from sand, and after the stone is removed from the mold the powdery substances may be readily .washed from the faces of the stone by water, whereupon the natural color and texture of the cast stone will be disclosed without the necessity "of employing any of the stone dressing or cutting operations commonly used heretofore. V t

The powdery substance used to treatthe stone-producing compound may 'readily' penetrate through the substance and become absorbed by the sand of the mold to thereby p dispose of this excess moisture;

may be employed in carrying out the present by the setting cement, and" excellent results are secured by covering'the desiredi surfaces of a sand m-oldwith a paste formed by mix} ing the waste material from a stone grinding This waste; material produced by acting upon artificial cast stone with anabrasion wheel consists largelyof ground particles of sand, Stoneand cement nently adhere to the stone-producing compound but may be readily washed with water 7 from the face-ofthe set cementstone.

a v so Whlle difierent water-pervious substances and is in the form of a finejpow'der. A paste i IllOIlObOllOLlS appearance.

are responsible for its hydraulicity are not clearly understood, nor is it entirely clear why some materials such as sand and particles of stone will be firmly gripped by cement, while other materials such as the finely pulverized substance above mentioned and secured as a by-product from the action of an abrasive wheel upon artificial stone will not firmly adhere to the cement. The very fine pulverized condition of this material appears to be more or less responsible'for the failure of the same to be gripped by the cement, and it is found that other finely pulverized material, such for example, as some forms of clay will not adhere firmly to cement and therefore may also be employed in carrying out the present invention.

When the'same pattern is used in forming a large number of sand molds the stones cast from these molds will all be substantially identical in size and appearance with the results that a building constructed from these similar stones may present a more or less It may therefore be desirable to vary the appearance of the faces of the stones that are exposed in the finished building, and this may be accomplished by throwing pebbles, stones or other rough bulky objects in the different sand molds so that they will impart different irregular faces to the revealed surfaces of the cast stones.

If the is stone-producing compound poured into a mold containing the pebbles or other rough objects just mentioned these objects will become set in the cement mixture unless steps are taken to prevent this. If,

however, the rough objects are covered in accordance with the present invention with 1 a coating of the pasty substance above described the desired rough and uneven surface will be imparted to the revealed face of the cast stone Without causing the pebbles or other roughobjects to adhere to the set cement mixture.

The variousfeatures of the present invention will be hereinafter described in connection with the accompanying drawings which illustrate good practical forms thereof.

In the drawings:

Fig. 1 is a top plan view of a sand mold.

Fig. 2 is a vertical sectional view through the mold of Fig. l and through a cast stone in the 'mold. 1 I

Fig. 3' is a similar view of a modified stone casting operation.

Fig. l is a perspective view of the cast stone of Fig. 2; and

Fig. 5 is a perspective view of the cast stone of Fig. v3.

The present invention may be employed i either in connection with sand molds or with permanently constructed molds formed of metal or other'durable material, since the powdery substance employed in accordance with the present invention will in either case prevent the cement of the setting mixture from adhering to the material forming the walls of the mold. The features of the present invention however are particularly well adapted for use in connection with sand molds, since the water pervious properties of the powdery material permits the excess water of the mixture to be readily absorbed by the sand of the mold. The invention is therefore shown and described herein in connection with sand molds.

In the drawings 10 designates a pile of molding sand which has been packed as usual about a pattern (not shown) and then the pattern has been removed from the sand leaving the depression or mold 11 into which a stone producing compound, which may consist of sand, crushed stone and hydraulic cement is introduced to form the cast artificial stone 12.

The mold 11 may be formed in any usual or preferred manner, but before the stoneproducing compound is poured into the mold, the bottom of the mold, or it may be, the bottom and sides of themold are treated, in accordance with the present invention with the fine powdery substance 13, which as above pointed out is capable of preventing the es tered onto the bottom and sides thereof. The

stone-producing compound containing hydraulic cement may then be introduced into the mold 11 as usual, and after the compound has set the cast stone may be removed from the sand and the faces thereof which have been protected by the material 13 from the sand may be washed with water to remove all particles of the material 13 and reveal the color and texture of the surface of the cast stone.

If the material 13 is applied to the mold in the form of a smooth paste it will form a thin smooth layer over the face of the sand and will in turn impart a smooth surface to the corresponding surface of the cast stone. If, however, the paste is relatively thickand is applied in uneven gobs to the mold a corresponding uneven surface will be imparted to the face of the cast stone, which may be desirable when stone having a more or less' uneven surface is desired. In either case the sand of the mold will quickly absorb the excess water of the paste and cause the latter to set or become firm, almost immediately,

and since this paste is pervious to water the excess water of the concrete mixture will penetrate through the paste 13 and W111 be absorbed by the sand of the mold to cause.

In the embodiment of the invention shown in Fig. 3 it is assumed that a cast stone with a roughened revealed face is desired and this water pervious paste-bespattered mold surface. a

4. As a new article of manufacture, an artificial stone having a cast face the surface of which is the impression of a water pervious, irregular paste-bespattered, sand mold surface composed of uneven areas having prominences of various shapes and sizes.

In testimony whereof, we have signed our names to this specification.

' JOHN B. BOSSI.

is produced by depositing pebbles or stones 1 17 in the mold 11, and over these stones 17 is placed a coating of the material 13 to prevent the pebbles from adhering to the cement. After the cement mixture of Fig. 3 is set and the cast stone is removed from the mold the revealed face 18 thereof will have a roughened surface consisting of hills and valleys as shown in Fig. 5, and the coating material 13 may be readily washed from the face 18 to show the color and texture of the cast stone.

If desired the appearance of the revealed face of the cast stone may be further varied by mixing any suitable coloring matter with the stone producing compound, or if preferred the coloring matter may be applied to the surfaces of the mold over the layer 13,

since the coloring matter will adhere sulficiently firmly to the cast stone to prevent its removal when the powdery substance 13 is washed therefrom.

What is claimed is:

1. The method of casting artificial stone which consists in providinga mold, apply:

ing to one or more faces of the mold a water pervious paste consisting of a mixture of water and a fine powder-like material which will not permanently unite with the cement and which is adapted to prevent the cement PAUL A. MAZZUCHELLI.

ing upon cast cement stone with an abrasion wheel to prevent the sand of the mold from adhering to the cast stone, then introducing into the mold a stone-producing mixture containing hydraulic cement, and washing the waste mixture from the cast stone to reveal the texture of the stone.

3. As a new article of manufacture, an artificial stone having a cast face the surface of which is the impression of an irregular 

